The Pokémon Summer Academy is almost over, but there's one more event left: the Pokémon Triathlon! Each Trainer will use two random Pokémon to race to a nearby lake and cross, then run on foot back to the Academy. Ash's Red Team is currently last in the overall points, but each Red Team member's points in this event will be added to the total score. So the race begins and the campers take off, led by Ash on a Spoink and Dawn on Dodrio. However, Ash's rival Angie has her Ariados sling some webs to swing her into first place. Once they reach the lake, Angie gets a Lapras, Ash gets a Mantyke, and the two remain ahead of the pack.
Jessie is dead last until a speedy Magikarp helps her move up several places. Conway decides to follow her, but Jessie thinks he's so creepy that she runs like the wind to get away from him. She even speeds past Ash and Angie, but Conway won't give up—so she has Seviper use Poison Tail to drive off Conway.
Battling is against the Triathlon rules, but before Ash and Angie can protest, Seviper's Poison Tail knocks Angie and her Shinx into a pit! By the time Ash pulls Angie to safety, Jessie and Conway are long gone.
However, Conway and Jessie are exhausted by the time they reach the Academy. Ash and Angie easily pass them, and Ash just manages to beat Angie to the finish line. Once everyone is done and the points are totaled, the Red Team has come from behind to win the overall award! Everyone celebrates the final night of camp with a bonfire, and Ash promises to visit Angie in Solaceon Town. But first things first: the next morning, he and his friends are off to Celestic Town for a Pokémon Contest!
Professor Rowan says that the last event will be the Pokémon Triathlon, and Ash gets pumped up. He begins talking to Dawn, Brock, and Angie about how he will win, when Angie buts in that she'll win. Dawn has to separate the two and Ash wishes Angie good luck by extending his hand for a handshake. Angie blushes, remembering how Ash saved her, and runs away. Ash is clueless as always about what just happened and begins prepping for the race. Conway pops up and has a talk with Dawn before running off as Rowan and Nurse Joy approach Ash and his friends. Brock launches into the usual routine before Croagunk stops him. Meanwhile, Jessie is busy getting pampered and reassures her team that they'll win while Meowth and James continue their duties.
The race is about to start, so Dawn recalls Piplup and Angie recalls Shinx. An aide fires the starting pistol and Jessie quickly takes the lead. She easily reaches the first checkpoint and receives a Hippowdon. Jessie begins arguing with the aide over Hippowdon's Speed while Ash and company reach the checkpoint. Ash, Dawn, Brock and Angie receive Spoink, Dodrio, Onix, and Ariados respectively and begin the first leg. Jessie finally starts out as other Trainers catch up and is propelled forward by Hippowdon's surprising speed. Back at the school, Rowan and the others monitor the race. With the race, Dawn has taken the lead with Ash closely following when Angie uses String Shot to propel herself into first. Picking up on this, many Trainers begin attacking each other. Conway takes advantage of this to pass them on Dugtrio.
Angie reaches the second checkpoint and trades Ariados for a Lapras. Ash closely follows, having passed Dawn, and receives a Mantyke. While Dawn and Brock trade for their Pokémon, Ash catches up to Angie when she again takes the lead with Ice Beam. Brock and Dawn, riding their Feraligatr and Sharpedo are passed by Conway and Floatzel and look on as he passes them. Jessie finally reaches the second checkpoint and argues with the aide over her position in the race and unfortunately receives a Magikarp. Surprisingly to James and Meowth looking on, Magikarp turns out to be incredibly fast.
In a practical dead heat, Ash and Angie reach the third checkpoint and return their Pokémon. Angie calls out Shinx and the third leg begins with both sprinting towards the end. Conway, Dawn, and Brock are approaching the end when Jessie speeds past them and reaches the third checkpoint. Conway quickly follows and Brock and Dawn follow from behind. Conway congratulates Jessie and somewhat creepily, begins to chase after her with Slowking as she tries to catch up to Ash and Angie. As Ash and Angie enter a cave, Jessie and Conway have managed to catch up with them and Jessie uses Seviper to attack them much to their and Conway's surprise. The ground beneath Ash and Angie begins to give way as Conway knocks out Seviper to slow Jessie down. Angie and Shinx barely manage to stop their fall by grabbing on a ledge, when Ash saves Angie again. Ash barely manages to pull Angie up and both sit down for a minute to catch their breath. Ash's relieved expression causes Angie to blush, but she quickly regains her composure when Ash point out that they have to make up a lot of ground and they begin racing again. Running at full speed, Ash and Angie quickly come close to the finish line where Jessie and Conway are exhaustively closing in. Seeing them approach, Jessie and Conway try to finish the race but due to their fighting, they are completely out of energy. Ash and Angie race for the finish and Ash wins by a nose. Ash begins celebrating while Angie has a moment of quiet thought. As other competitors cross the finish line, Conway and Jessie crawl across it and collapse.
The victory gave the Red team just enough points to win the challenge and all of the members receive a plaque after Rowan makes a quick speech. As a final celebration for the end of the Summer Academy a bonfire is lit and a buffet laid out. James and Meowth have a conversation about how they had a nice experience while Jessie stuffs her face and says goodbye to the students who waited on her hand and foot. Over by the gate, Angie is sitting, looking at the stars when Ash comes over. Angie asks Ash why he saved her, and Ash, clueless to her crush on him, replies that he is her friend, making her look a little disappointed. Angie and Ash end their rivalry on a note of friendship. In the morning, everyone bids goodbye to their friends and Ash and his friends wave to Angie before heading towards Celestic Town and Dawn's next Pokémon Contest.